Memory devices are typically provided as internal, semiconductor, integrated circuits and/or external removable devices in computers or other electronic devices. There are many different types of memory including volatile and non-volatile memory. Volatile memory can require power to maintain its data and can include random-access memory (RAM), dynamic random access memory (DRAM), and synchronous dynamic random access memory (SDRAM), among others. Non-volatile memory can provide persistent data by retaining stored data when not powered and can include NAND flash memory, NOR flash memory, read-only memory (ROM), and resistance variable memory such as phase change random access memory (PCRAM), resistive random access memory (RRAM), and magnetic random access memory (MRAM), among others.
Memory devices can be utilized as volatile and non-volatile memory for a wide range of electronic applications in need of high memory densities, high reliability, and low power consumption. Non-volatile memory may be used in, for example, personal computers, portable memory sticks, solid state drives (SSDs), personal digital assistants (PDAs), digital cameras, cellular telephones, portable music players, for example, MP3 players, and movie players, among other electronic devices. Data, such as program code, user data, and/or system data, such as a basic input/output system (BIOS), are typically stored in non-volatile memory devices.
One of a number of states (e.g., resistance states) can be set for a resistance variable memory cell. For example, a single level cell (SLC) may be programmed (e.g., written) to one of two states (e.g., logic 1 or 0), which can depend on whether the cell is programmed to a resistance above or below a particular level. As an additional example, various resistance variable memory cells can be programmed to one of multiple different states corresponding to respective digit patterns (e.g., 10, 01, 00, 11, 111, 101, 100, 1010, 1111, 0101, 0001, etc.). Such cells may be referred to as multi state cells, multi-digit cells, and/or multilevel cells (MLCs).
The state of the memory cell can be determined (e.g., read), for example, by sensing current through the cell responsive to an applied interrogation voltage. The sensed current, which varies based on a voltage level of the cell, can indicate the state of the cell (e.g., the binary data stored by the cell). However, the voltage level of the cell may undesirably change due to various reasons, which can result in erroneous sensing of a memory cell.